Conventional swimming pools and hot tubs include systems for recirculating the water in the pool or tub. As the pool water is recirculated, it is typically filtered and cleaned and may also be heated, if desired. Some pools have an automatic float level system. However, the majority of home pools do not have such a system for adding water to make up lost water due to evaporation and other causes. The home owner simply uses a garden hose from time to time to add water. This is time consuming and inconvenient.
Pools that have an automatic water level system often rely upon one or more float valves that are associated directly with the inlets and outlets for water entering and leaving the pool. When the water level in the pool rises or falls, the floats mechanically actuate valves to cause water to enter or leave the pool. Examples of these mechanical types of systems are shown in U.S. Pat. Nos. 2,809,752, 3,837,015, and 3,895,402. Unfortunately, because the floats and valves of these systems are quite visible and located in or near the pool, they are vulnerable to damage or vandalism from swimmers. The floats can be broken or rendered inoperable, thus negating the effectiveness of the system.
Systems are known that incorporate an overflow tank or sump that is separate from the pool. The level of the water in the separate tank is used as an indicator-of the level of water in the swimming pool. This separate tank is then monitored using a sensor, float, or other device. Examples of these types of systems are shown in U.S. Pat. Nos. 5,804,080, 4,445,238 and 3,895,402. These systems have the advantage of allowing the components necessary to measure the liquid level in the pool to be located away from the main pool. However, because a separate tank is required to be associated with the pool, these systems must be installed when the pool is originally constructed. Otherwise, a retrofitting must be done wherein portions of the concrete surrounding the pool are broken up to install the separate tank and associated components. This can be costly and time-consuming and requires that the pool be closed down during installation.
U.S. Pat. No. 5,878,447 shows a sensor for sensing the water level and sending a radio frequency transmission to a receiver. The receiver is electrically connected to a solenoid valve of a water source. While such a system is workable, improvements are desirable.